package com.guosheng.nettytest.three;


import org.apache.ibatis.annotations.Select;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;

public class TimeClientHandler implements Runnable{

    private String host;
    private int port;
    private Selector selector;
    private SocketChannel socketChannel;
    private volatile boolean stop;

    public TimeClientHandler(String host,int port){
        this.host = host == null ? "127.0.0.1":host;
        this.port = port;
        try {
            selector = Selector.open();
            socketChannel = SocketChannel.open();
            socketChannel.configureBlocking(false);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void run() {

        try {
            doConnect();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(1);
        }
        while(!stop){
            try {
                selector.select(1000);
                Set<SelectionKey> selectedKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectedKeys.iterator();
                SelectionKey key = null;
                while(it.hasNext()){
                    key = it.next();
                    it.remove();
                    try {
                        handleInput(key);
                    } catch (Exception e) {
                        e.printStackTrace();
                        if(key != null){
                            key.cancel();
                            if(key.channel() != null){
                                key.channel().close();
                            }
                        }
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
                System.exit(1);
            }
        }
        //多路复用器关闭后，所有注册在上面的channel和pipe等资源都会被自动去注册并关闭，所以不需要重复释放资源
        if(selector != null){
            try {
                selector.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void handleInput(SelectionKey key)throws  IOException{
        //告知此键是否有效
        //键在创建时有效的，并在被取消，其通道已关闭或者其选择器已关闭之前保持有效，有效返回true
        if(key.isValid()){
            //判断是否连接成功
            SocketChannel sc = (SocketChannel)key.channel();
            if(key.isConnectable()){
                if(sc.finishConnect()){
                    sc.register(selector,SelectionKey.OP_READ);
                    doWrite(sc);
                }else{
                    //连接失败进程退出
                    System.exit(1);
                }
            }

            if(key.isReadable()){
                ByteBuffer readBuffer = ByteBuffer.allocate(1024);
                //将字节序列从此通道中读入给定的缓冲区，返回的是读入的字节数组的长度
                int readBytes = sc.read(readBuffer);
                if(readBytes > 0 ){
                    //使缓冲区为一系列新的通道写入或相对获取操作做好准备，它将限制设置为当前位置，然后将位置设置为0
                    readBuffer.flip();
                    //remaining()返回当前位置与限制之间的元素数
                    byte[] bytes = new byte[readBuffer.remaining()];
                    //此方法将此缓冲区的字节传输到给定的目标数组中
                    readBuffer.get(bytes);
                    String body = new String(bytes,"utf-8");
                    System.out.println("Now is ：" + body);
                    this.stop = true;
                }else if(readBytes < 0 ){
                    //对端链路关闭
                    key.cancel();
                    sc.close();
                }else{
                    //读到0字节，忽略
                }
            }

        }
    }

    private void doWrite(SocketChannel sc)throws IOException{
        byte[] req = "query time order".getBytes();
        ByteBuffer writeBuffer = ByteBuffer.allocate(req.length);
        //将给定的字节数组写入此缓冲区的当前位置，然后改位置递增
        writeBuffer.put(req);
        writeBuffer.flip();
        sc.write(writeBuffer);
        //告知在当前位置和限制之间是否有元素，当且仅当此缓冲区至少还有一个元素时返回true
        if(!writeBuffer.hasRemaining()){
            System.out.println("send order 2 server succeed");
        }
    }

    private void doConnect() throws IOException{
        //如果直接连接成功，则注册到多路复用器上，发送请求消息，读应答
        //连接此通道套接字
        if(socketChannel.connect(new InetSocketAddress(host,port))){
            socketChannel.register(selector, SelectionKey.OP_READ);
            doWrite(socketChannel);
        }else{
            socketChannel.register(selector,SelectionKey.OP_CONNECT);
        }
    }
}
